Clip

ABSTRACT

A CLIP THAT IS A GENERALLY U SHAPED WIRE OF UNIFORM CROSS SECTION WITH AN INWARDLY DIRECTED FACE THAT HAS A CURVED INNER EDGE THAT BROADENS OUT TOWARD THE FACE&#39;&#39;S OUTER EDGE. THE CLIP HAS A GROOVE ON EACH SIDE OF ITS INNER EDGE.

Feb. 23, 1911 i. ROBERTS 3,564,663

CLIP

Filed Dec. 31, 1968 INVENTOR JOHN'EROBERTS BYzWM/ ATTORNEY United StatesPatent O U.S. Cl. 2430.5 3 Claims ABSTRACT OF THE DISCLOSURE A clip thatis a generally U shaped wire of uniform cross section with an inwardlydirected face that has a curved inner edge that broadens out toward thefaces outer edge. The clip has a groove on each side of its inner edge.

This invention relates to a generally U-shaped deformable sealing clipadapted to be applied around the neck of a flexible container such as aplastic bag to provide an air tight seal of the character required whenthe container is evacuated to maintain the product therein under avacuum.

In packaging vacuum packed products, such as meat, cheese, poultry, andthe like, it is essential that a perfect and long lasting seal beapplied so as to prevent spoilage of the product by the leakage of airinto the container. Heretofore numerous attempts have been made toimprove clips to the end that optimum sealing effect is achieved. Such aclip is the so called cross over clip which comprises a U-shaped clipdeformed around the mouth or neck of the container so that the opposedlegs of the clip cross each other during the deforming step and arebrought into side by side closely adjoining relationship, see forexample U.S. Pat. No. 3,400,433 and the patents cited therein.

It is important in providing an air tight seal to apply extremely highradially inwardly directed compressive forces on the material of thecontainer mouth in order to compress the material from which the packageis made and produce a leak free seal. This is especially true in thecase of bags and other containers made of the tough modern resilientplastics.

One of the common prior art clips had a round crosssection or, in otherwords, the wire from which the clip was made was cylindrical. Theoverall shape of the clip was a U, 2 legs and a connecting bightportion. Thus when the clip was applied to seal the neck of a plasticbag the innermost edge of the curved side of the cylindrical clip bodywould be most firmly engaged against the bag when the clip was crimpedaround the bags neck. The greatest force applied against the plastic bythe deformation of the clip was concentrated at this innermost curvededge.

With the rounded side of the clip engaging the bag, the bag wasgenerally not damaged because it was deformed in a channel with agradually increasing pressure and compressed along the curved clipsurface. When such clips were used it was necessary to use clips made.from a fairly heavy gauge cylindrical wire in order to providesuflicient deformed strength to prevent the resiliency of the sealed bagfrom forcing the clip to a partially open position and also to preventdislodgment of the clip from the neck of the bag, particularly when theneck was cut very closely adjacent to the clip. Clipped plastic bags aregenerally severed closely adjacent to the clip to provide a tightpackage that is both pleasing to the eye and requires no more space inthe display counter or in the shipping cartons than absolutelynecessary. These prior art clips necessarily required additional widthin the feed track in order to accommodate the most outwardly extendingdimension of their outer cylindrical edge. This cylindrical outer shapeoften caused the clips to individually angle irregularly in the feedtrack by cocking around thus causing the machine to jam. To preventthis, it is often necessary to provide elaborate inner connection of theclips so that individual clips cannot cock in the feed channel.

It has been found that the sealing effect of the clip is proportional tothe inward deformation of the packaging material engaged by the innersurface of the clip and the clips resistance to being sprung open by theresiliency of the packaging material or slipping from engagement withthe packaging material. The section modulus or holding strength of theclip is a property of the shape of the cross section and its magnitudeis an indication of the resistance the clip will offer to deformation,both primary and secondary or immediately and with time.

Accordingly, it is an object of my invention to provide a clip adaptedfor use in conventional clipping apparatus that will create and maintainan efficient seal around the neck of a flexible container such as aplastic bag.

Another object of this invention is the provision of a clip that isparticularly efficient in producing an airtight seal.

A further object of this invention is to provide a clip that will have alower incidence of jamming in the feed track of conventional clippingmachines.

Other objects and advantages will be apparent from the followingspecifications and from the drawings.

Briefly stated in carrying out my invention, in one form thereof, I haveprovided a generally U-shaped clip made from a wire of generally uniformcross section throughout its length. The Wire has an inwardly directedside that has a diminished width at its inner edge and an enlarged widthat its outer edge. The Wires cross section is generally that of anisosceles triangle with rounded corners. In its preferred form, the baseof the triangle is disposed outwardly and the two equal sides and thebase have relatively flat planar dimensions between the rounded corners.

In another form of my invention, by another aspect thereof, the entireinwardly directed side is an even arc in cross section. In still anotherform, by another aspect of my invention the inwardly directed side hasan eliptical point with a groove on each side of the point.

FIG. 1 is a semischematic side view showing a clip of the presentinvention with an associated punch and die at the point at which thelegs of the clip are about to be deformed inwardly toward each other;

FIG. 2 is a greatly enlarged typical cross section along line 2-2through the preferred form of the clip of the present invention;

FIG. 3 is a cross section similar to that of FIG. 2 but showing anotherform of my invention;

FIG. 4 is a cross section similar to FIG. 3 showing still another formof my invention;

FIG. is a cross section through the punch 12 of FIG. 1 along line 2-2;

FIG. 6 is a cross section through the mouth of a sealed containershowing the clip deformed therearound; and,

FIG. 7 is a fragmentary side elevation of a plastic bag showing the clipof FIG. 2 applied thereto.

As in described in greater detail in US. Pat No. 3,3 83,- 746 which isowned by the same assignee as the present application, the clip 10 isgenerally adapted to be urged against a die 11 by a punch 12 in order todeform the clip around the neck 13 of the container to be sealed,referring to FIG. 1. The undeformed clip 10 has a pair of opposed legs14 and 15 which are joined together by a curved bight section 16. Thelegs 14 and 15 are straight and may be considered parallel except thatit is preferable that they flair outwardly slightly at their free endsto facilitate controlled feeding of the clip along the feed track (notshown) and over the gathered bag neck. The clip may be formed of variousmaterials, including steel and aluminum, and it is preferably coldworked to the shape shown in FIG. 1.

The cross section of the clip 10 shown in FIG. 2 is generally that of anisosceles triangle with rounded corners at the base angles or corners 17and 18 and a broadly rounded end or inner edge 20 at the apex angle. Theinner edge as shown in FIG. 2 has a larger circumference than the outeredges. The sides 21 and 22 and the base side 23 of the triangle arerelatively straight between their curving junctures. The cross-sectionalcontour of the clip is such that the broadly curving tip 20 is presentedto the material to be compressed and sealed. The sides 21 and 22 divergeaway from the inner tip 20. The punch 12 engages against the side 23. Itis thus apparent that the inner surface of the punch that engages theflat side 23 of the clip 10 would preferably have the cross sectionalshape shown in FIG. 5 which is taken substantially along line 22 ofFIG. 1. It will be seen that this provides a wide engagement of the clipacross its entire upper surface by the punch. The punch has thecapability of shifting the clip slightly in position if necessary toattain proper engagement because of its curved shoulders 25 and 26 whichengage the outer rounded corners 17 and 18 of the clip. The land 29engages the side 23 of the clip. Thus the pressure applied to the clipby the punch 12 is distributed over a wide area of engagement.

The inside face of the clip diminishes at its inner edge 20 thusproviding a high force at the strongest point of engagement against theplastic bag about which the clip is crimped. Because of the rubberyproperties of the plastic from which bags are typically made the plasticis squeezed out from under the point 20 and bulges up along the slopingsides of the clip 21 and 22. This has the desirable characteristic ofextending the area of the closure by squeezing the plastic togetheralong each side of the point 20 and also reduces any tendency of theinner edge of the clip to penetrate or sever the plastic walls of thebag at relatively high engagement pressures. The large mass of the clipis most distant from the inner point of the clip which is the clip areaagainst which the bag pushes most strongly as a result of its naturalresiliency which continuously pushes outwardly against the clip tendingto spring the clip open. This structural design in the clip provides astrong holding characteristic in the clip for the particular mass ofmaterial in the clips total cross section. All of this works to providea superior and long-lasting seal and to reduce the likelihood that thecontainer will leak. This cross sectional distribution of the massenables clips of a given closing and holding capacity to be made from asmaller quantity of metal, saving material cost and shipping cost. Thisnew clip structure also enables an easier deformation of the clip intoits sealing position.

Another form of the clip of this invention is shown in FIG. 3. This formof the clip is made by either splitting a piece of wire in half circlesor by forming the wire originally in this shape. In cross section, iftaken along line 22 of FIG. 1, the clip 30 would have a flat outersurface 31 and a curved inner surface 32. The operation of this clipwould be substantially the same as that described with respect to theclip shown in FIG. 2, the primary disadvantage being that it requiresslightly more material to manufacture a clip that will provide a giveneffective closing and holding job.

The clip cross section shown in FIG. 4 would have the highest economy ofmaterials but, if made of a soft material such as aluminum, the clip 33might collapse under the considerable closing pressure supplied by thepunchs operation thus reducing the resistance of the clip to beingopened outwardly. In some instances the clip could so collapse that itwould assume the shape of a wide band and reduce the depth to which theclip would go as it deformed the plastic bag neck. This clip crosssection would also be represented by a cross section taken through aclip as shown at line 22 of FIG. 1. The clip would have a somewhatrounded upper surface 34, which might aid in centering the clip if itwere to be used in a clipping device having a punch that would have acontinuous arc if viewed in a cross section similar to the cross sectionof FIG. 5.

Sides 35 and 36. have grooves 37 and 38, respectively, formed in them toreduce the quantity of material required to manufacture the clip. Ofcourse, the raising of the upper surface 34 into a slight curve consumessome of the material saved in the formation of the grooves 37 and 38.The point 39 is curved as previously described so that it will notpierce the surface of the bag. The curve in this particular instance issharper than the curves of clips 10 and 30. In certain instances, whereplastic materials that are very easily deformed are used the materialsmay actually come up into the grooves 37 and 38 locking this clip evenmore securely in position against slippage. Obviously some features ofthese various cross sectional structures can be combined, for example,there could be instances when the rounded side 34 would be advantageouswith the uniform arc 32.

The use of the above described clip for sealing a vacuumized containerhas been emphasized because prior art clips, which this clip is intendedto replace, are widely used for this purpose. However, the clip of thisinvention is obviously equally applicable to other uses, such as forexample, sealing containers that are subjected to internal pressurerather than a vacuum. Of course, the clip gives a superior closure anytime a clip closure is desired. When the clip is used on a bag that isto be hung up with the product pushing down against the clipped neck theresistance of the clip to slipping along the length of the containerneck is especially important. The individual clips need not be formedfrom wire but could be individually shaped in any way, their lengthstill having the general characteristic of a strand of wire and thuscalled a Wire in this application.

I claim:

1. A generally U-shaped clip for forming a tight seal around an articlesuch as the mouth of a flexible container comprising a pair of opposedlegs and a bight section connecting the corresponding ends of said legs,said legs being adapted to be deformed toward each other into encirclingrelation with such article, said clip being formed of a wire ofgenerally uniform cross section throughout its length, said wire havingan inwardly directed side that has a diminished width at its inner edgeand an enlarged width at its outer edge and a functional groove formedin said clip on each side of the inner edge between said inner edge andsaid outer edge, said grooves extending the length of said wire.

2. The clip of claim 1 wherein said grooves are formed to cause the clipto collapse under pressure and form a widened band.

5 6 3. The clip of claim 1 wherein said grooves are formed FOREIGNPATENTS to receive materials to which the clip is applied to lock 793126 4/1958 Great Britain 85 49 said clip securely in position againstslippage. 1O5:606 9/1942 Sweden 85 49 716,780 10/1931 France 85-49References Cited 5 t UNITED STATES PATENTS DONALD A. GRIFFIN, PrimaryExammer 3,400,433 9/1968 Klenz 24- 30,5 US. Cl. X-R- 3,473,430 10/1969Niedecker s5 49 8549

